The present invention relates to a grille shutter device for selectively opening and closing, with fins, a grille opening in the front grille of a vehicle.
A typical front grille on the front side of a vehicle has a grille opening for introducing outside air to the front side of the radiator located in the engine compartment. The outside air that has passed through the grille opening cools coolant in the radiator, so that the engine is prevented from overheating.
However, when the temperature of the outside air is low, for example, in the winter, the outside air that contacts the radiator after passing through the grille opening degrades efficiency of the warm-up performed immediately after the engine is started. Also, when the vehicle is traveling at a high speed, the outside air might excessively cool the coolant in the radiator. Further, the drawn-in outside air might produce turbulence in the engine compartment, which increases the air resistance to the vehicle.
In this regard, a type of grille shutter device has been proposed that includes fins at the grille opening. The fins are opened or closed by an actuator, for example, in accordance with vehicle speed and the temperature of coolant (for example, refer to Japanese Laid-Open Patent Publication No. 2010-223150).
The grille shutter device disclosed in Japanese Laid-Open Patent Publication No. 2010-223150 controls opening and closing of the fins in accordance with the direction of rotation of the actuator main shaft. When opening the fins, the main shaft of the actuator is rotated in a forward direction. When closing the fins the main shaft is rotated in a reverse direction. That is, when the swinging direction of the fins is switched for opening or closing the fins, the rotational direction of the actuator main shaft needs to be switched. This complicates the control for opening and closing the fins.